Could you tell me —-It is hard to say.

In Copenhagen Climate Conference，rich countries promised to________a fund of $100 billion a year by 2020 to help developing countries.[ ]

Which is ____ country, America ____ Canada?

Good dietary sources of calcium should ________leafy green vegetables, fish, yogurt, tofu and breakfastcereals(谷类食物).[ ]

I lost a book, ______I can’t remember now.